Patterns of Cancer Care and Association with Survival among Younger Adolescents and Young Adults: A Population-based Retrospective Cohort Study.

Background: Younger adolescents and young adults may receive care from either adult or pediatric oncologists. We explored patterns of care in this population and whether survival is associated with provider type. Methods: Utilizing the California Cancer Registry, we examined a cohort of 9,993 AYAs diagnosed with cancer aged 15-24 years from 1999-2008. Provider type (adult/pediatric) was determined by individual physician identifiers. For provider type, multivariable logistic regression models were adjusted for age, sex, race/ethnicity, socioeconomic status, diagnosis, and stage. For observed survival, Cox proportional hazard models were additionally adjusted for provider type. Odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (95%CI) were determined. Results: Most patients saw adult providers (87.3% overall; 72.7% aged 15-19 years). Patients with acute leukemia, sarcoma, and central nervous system (CNS) malignancies more often saw pediatric providers (OR [95%CI] adult versus pediatric 0.48 [0.39-0.59], 0.74 [0.60-0.92], 0.76 [0.60-0.96], respectively); those with germ cell tumors and other cancers, including carcinomas, more often saw adult providers (2.26 [1.72-2.98], 1.79 [1.41-2.27], respectively). In aggregate and for most cancers individually, there was no survival difference by provider type (overall HR [95%CI] 1.00 [0.86-1.18]). Higher survival was associated with pediatric providers for CNS malignancies (1.63 [1.12-2.37]) and rhabdomyosarcoma (2.22 [1.03-4.76]), and with adult providers for non-Hodgkin lymphoma (0.61 [0.39-0.96]). Conclusions: Most AYAs 15-24 years old are treated by medical oncologists. In general, survival was not associated with provider type. Impact: Current patterns of care for this population support increased collaboration between medical and pediatric oncology, including joint clinical trials.